Gas generator and cavitator for gas generation

ABSTRACT

A gas generator for gasification of liquids, e.g. vapour from water, including a main rotor body being rotatably mounted to a static support framework to rotate around a rotor body center axle. The main rotor body having main rotor body channels for guiding a flow of a liquid from a rotor body channel inlet towards a rotor body channel outlet located further away from the rotor body center axle than the rotor body channel inlet so liquid in the rotor body channel is forced towards the rotor body channel outlet by centrifugal forces. The main rotor body has cavitator channels connected to the rotor body channel outlet. The cavitator channels have cavitation element to induce a differentiated pressure within the liquid in the cavitator caused by centrifugal forces induced by the rotation of the main rotor body inducing cavitation of the liquid flowing through the cavitator channels.

FIELD OF INVENTION

The invention relates to a gas generator which generates a gas bycavitation of a liquid, e.g. water. The invention also relates to thegas generator and a cavitator suitably used therein. The invention couldfor example be used for desalination of sea water.

BACKGROUND ART

Cavitation is a known method for gasification of liquids. Cavitation isgenerally referred to as the formation, growth and subsequent collapseof gas, e.g. vapour if water is used as the liquid, inside a liquid. Ingeneral, there is a need for causing rapid and local changes in thehydrostatic and hydrodynamic conditions of the liquid. There aredifferent ways known to cause cavitation of liquid such as adding highlevels of energy to the liquid by irradiation, e.g. by highly energeticwaves such as laser light or high energy particles such as electrons, orby subjecting the liquid to high mechanical forces and stress. Ingeneral, the use of subjecting liquid to highly energetic irradiation issuitably used for small scale experiments but is costly to be used forindustrial applications. Mechanically induced cavitation seems to bemore promising in order to be used for large scale cavitation ofliquids. In mechanically induced cavitation, the liquid to be treated isgenerally subjected to high flow speeds and guided through a flow pathincluding flow guides and flow restrictions, e.g. venturi passages, inorder to subject the liquid to the desired hydrostatic and hydrodynamicconditions.

Regardless of how changes in hydrodynamic conditions are caused,different types of constrictions may be employed to cavitate a fluid.However, movement of large volumes of fluid at the requisite speedthrough each of these constrictions to effect hydrodynamic cavitationrequires high energy input. As a result, achieving cavitation inducedevaporation from conventional hydrodynamic solutions remains impracticaland unreasonably expensive.

A device used for cavitation of liquids by mechanically inducingcavitation in a fluid or liquid is for example disclosed in US 2016/185624 which describes a multi-stage cavitation assembly. The liquid orfluid is subjected to a first cavitation inducing feature followed bysecond cavitation feature which occurs after the fluid is subjected toflow guiding means slowing down the speed of the fluid and is directedto the second cavitation feature. The device described in US 2016/185624 is described to be suitably used for fluid treatment such as waterremediation.

DISCLOSURE OF INVENTION

The invention relates to a gas generator for gasification of liquids.The liquid may for example be water such that vapour is produced in thegas generator. The gas generator may for example be used for vaporizingsalt water in order desalinate the water to produce potable water. Thegas generator comprises a main rotor body being rotatably mounted to astatic support framework and the main rotor body is arranged to rotatearound a rotor body main axis. The main rotor body comprises one orseveral rotor body channels having a rotor body channel inlet and arotor body channel outlet. The channels are designed for guiding a flowof a liquid from the rotor body channel inlet, which is located at adistance R1 in the radial direction from the main axis, towards therotor body channel outlet which is located at a distance R2 in theradial direction from the rotor body main axis. The rotor body channeloutlet is located further away from the rotor body main axis than therotor body channel inlet, i.e. R2>R1, such that a liquid in the rotorbody is forced from the rotor body channel inlet towards the rotor bodychannel outlet by centrifugal forces as the main rotor body rotatesaround the main axis. Hence, the rotation of the main rotor body may beused to induce a pumping effect in the rotor body channel. The mainrotor body further comprises one or several cavitators each onecomprising one or several cavitator channels. The one or severalcavitator channels are provided with a cavitator channel inlet and acavitator channel outlet. The cavitator channel inlet is fluidlyconnected to the rotor body channel outlet for guiding the liquid flowto the cavitator for cavitation of the liquid. The cavitator channelinlet is located closer to R2 than R1 and is preferably designed to belocated in close vicinity to the rotor body channel outlet at a distanceR2 from the main rotor body axle. In general, the cavitator channel andmain rotor body channel are designed such that the flow from the rotorbody channel outlet is directly transferred to the cavitator channelinlet in such a way that the complete flow from the rotor body outlet isforced to enter into the cavitator channel inlet. It is in generaldesired to locate the cavitator channel inlet at R2 as well, inparticular it is desired to avoid that the cavitator channels have anextension such that the cavitator outlet will be positioned at aposition considerably closer to the axis of rotation of the main rotorbody than the cavitator outlets in order to avoid a liquid to be forcedto travel in a direction against the centrifugal forces created by therotation of the main rotor body. The cavitator channel is designed tocomprise cavitation inducing means, e.g. flow guiding or restrictingmeans, wave shaped channel walls, protrusions and widenings, bends,surface irregularities such as cavitation generating indentations or acombination thereof. The cavitation inducing means are present in orderto induce a differentiated pressure within the liquid in the cavitator.A differentiated pressure will arise from the inertia of the liquid andthe centrifugal forces due to the rotation of the main rotor body as theliquid pass through the cavitation inducing means in the cavitatorchannel so as to induce cavitation in the liquid flowing through thecavitator. Hence, it is an advantage to locate the cavitator with itscavitation inducing means at a distance from the axes of rotation of themain rotor body since the forces acting on a liquid at the samerotational speed will be stronger at a longer radial distance from theaxes of rotation. The gas generator could thus be designed such that therotor body channel is mainly designed to guide the liquid to becavitated in the cavitator from an inlet at the axis of rotation or aradial distance R1 close to the axis of rotation to an outlet at asignificantly longer radial distance R2 from the rotational axis of themain body without the aim of inducing cavitation. In the presentarrangement, the rotor body channel will function mainly as a transportchannel while also increasing pressure and flow rate of the liquid andthe built up pressure in the main rotor body channel from the rotationof the main rotor body will be used in the cavitators for cavitation ofthe liquid.

Hence, the gas generator is designed to induce a fast flow of the liquidthrough the main rotor body and the cavitators by a fast rotation of themain rotor body in order to induce cavitation in the liquid flowing inthe cavitator. The cavitation inducing means could for example includethat a cavitator channel is designed to comprise several curves orbends, e.g. a wave shaped pattern, causing a liquid flowing through thecavitator channel to change directions so as to cause a differentiatedpressure within the liquid in the cavitator. Using a curved channel,e.g. a wave shaped channel, may not usually have any major impact forinducing cavitation. However, at the very large speed the main rotorbody is intended to rotate, e.g. having a rotational speed of 5 000 rpmup to 30 000 rpm, there will be a considerable impact from the change ofdirections of the channel and flow of fluid there through. By designingthe channels with its curves and bends such that the change ofdirections will cause indifferent pressure profiles on a liquid flowingtherein at different portions of the channel when subjected to thecentrifugal forces from the rotation of the main rotor body will inducecavitation in the fluid. At certain locations in the channel, there willbe compressive forces acting on the fluid and its molecules andparticles. At other locations there will be forces acting to separatethe liquid molecules and if these forces are made strong enough theformation of small bubbles will appear. These bubbles will generallyimplode shortly after they have been formed as long as the liquid iscontained in a restricted environment such as the confined space of thecavitator channel. Hence, the strong forces enabling a differentiatedpressure within the liquid in the cavitator arises from the inertia ofthe liquid and the centrifugal forces caused by the rotation of the mainrotor body at a sufficiently high speed thereby causing the waterflowing through the cavitator to cavitate when subjected to flowrestrictors, bends or other cavitation inducing means.

The main rotor body is preferably designed to comprise a multitude ofcavitators being located equidistant from each other and equidistantfrom the main rotor body axis. A symmetric rotor is of importance due tothe large forces arising from the high speed rotational motion of themain rotor body. Hence, there are preferably at least two equallydesigned cavitators comprised in the main rotor body being symmetricallylocated around the rotor body main axis.

The main rotor body may further be designed to comprise walls defining arotatable container having an interior main rotor body space to whichthe vaporized liquid is released from the cavitators. The interior spaceof the main rotor body could be designed to be bell shaped. This designcould also be described as being shaped as the lower half of an hourglass or as a truncated cone. This design could also be described ashaving a cross sectional area of the main rotor body perpendicular toits longitudinal axis which decreases towards the outlet at the top ofthe main rotor body. The main rotor body could for example be designedsuch that each cross section of the main rotor body perpendicular to therotational axis forms a circular segment. The main rotor body shouldhave a rotational symmetric shape around its rotational axis in order toavoid unbalance in the main rotor body.

Even though it is disclosed above how a casing may be used for the gasgenerator and a specific shape of such a casing may be designed, the gasgenerator functions also without a casing or having a casing of anothershape.

The main rotor body casing forming part of the main rotor body may bedesigned to have a main rotor body outlet at its upper portion. The mainrotor body casing may be designed to have a reduced cross sectional areaperpendicular to the rotor body centre axle in its upper part comparedto a cross sectional area in lower part of the main rotor body casing,e.g. by designing the main rotor body casing such that the mean crosssectional area of the rotatable container formed by the main rotor bodycasing will decrease in along its length from the lower part to theupper part. This may for example be achieved by having a bell or coneshaped main rotor casing.

The gas generator may be designed such that the main rotor body iscomprised in an inner casing forming part of the static supportstructure. The inner casing could be used as a pressure chamber in orderto provide a vacuum or low pressure environment in which the main rotorbody is rotating. By providing a low pressure environment will thefrictional forces acting on the main rotor body while rotating bedecreased.

If the gas generator comprises a main rotor body casing, the casing maybe designed to comprise a main rotor body outlet which is adapted tocooperate and fit into an outer container space gas inlet. If the gasgenerator is further provided with an inner casing in which the mainrotor body is located, the main rotor outlet could be designed to becomprised in an inner casing upper wall. The main rotor body outlet andthe outer container space gas inlet may be designed such that theopenings have an overlapping area. The outer container space gas inletcould be designed to have a larger cross sectional area than the mainrotor body outlet such that there is a gap created between the outercontainer space gas inlet and the main rotor body outlet. By designingthe gas generator in this way, it may be possible to use the flow of gasfrom the main rotor body space to create and maintain a vacuum or lowpressure zone in the inner container space due to the venturi effect ofthe flowing gas.

The main rotor body space could further be designed to comprise a flowrestrictor encircling the centre axle. The flow restrictor is intendedto be located between the main rotor body gas feed openings, where gasproduced in the cavitators enters the main rotor body space, and themain rotor body outlet. The purpose of including such a flow restrictoris to cause solid matter contained in the gas to be separated from thegas flow. Particles entrained in the gas flow will be separated from thegas flow by the impact of hitting the flow restrictor.

The main rotor body space could be designed to comprise main rotordrainage outlets (207). The drainage outlets could be located at in thebottom region of the main rotor body space, e.g. in a drainage reservoirrunning along the circumference at the bottom of the main rotor bodyspace. The drainage outlets will discard solid matter which has beenseparated from the gas flow and fallen down to the bottom of the mainrotor body space together with a portion of the fluid.

The gas generator could be designed to comprise a fixed outer casing inwhich the fixed inner casing is comprised. The fixed inner casingdefining an inner container space could be used as a vacuum or lowpressure chamber for the main rotor body. The flow of gas produced bythe cavitators could be guided from main rotor body via an outercontainer space gas inlet to the outer container space. The outercontainer space may thus function as a reservoir for gas produced by thecavitators.

The outer container space may further comprise liquid supply conduits inwhich liquid to be fed to the main rotor body is preheated by the gasgenerated in the main rotor body flowing through the outer containerspace. The system can be controlled such that the gas flowing throughthe outer container space is cooled down to condense in the outercontainer space. The condensed gas may be collected from the outercontainer space via an outer container space outlet in order to becollected in tanks or further distributed via a piping system.

In order to establish a flow of liquid to be supplied to the gasgenerator, the main rotor body may be designed as a pump unit such as ascrew pump or Archimedean screw. A screw pump will provide for a pumpingeffect when the main rotor body rotates in order to pump a liquid from aliquid supply reservoir via pump channels forming part of the main rotorbody channels when the main rotor body is rotating. The pumping ofliquid could of course be achieved by any other kind of pumpingarrangement if desired.

The main rotor body is preferably designed to include at least twocavitators in order to balance the rotating main body. Any kind ofcavitators could be used in order to produce gas from cavitating theliquid. A particularly useful kind of cavitators to be used in the gasgenerator is designed to have an inner cavitator rotor arranged torotate relative an outer cavitator stator. The rotational movement ofthe cavitator rotor may be achieved by designing the cavitator to inducea rotational movement by the water flowing through the cavitator fromthe cavitator inlet to the cavitator outlet. One way of achieving apropelling force for rotating the cavitator rotor is to design thecavitator rotor with turbine blades. Still another way of producing arotational movement is to design cavitator channels to direct theflowing liquid to provide a rotational force.

In case cavitators having a cavitator rotor and a cavitator stator isused, they can be arranged in the main rotor body such that their axesof rotation are essentially perpendicular to the main rotor body centreaxle being the axis of rotation of the main rotor body. The cavitatorscan also be arranged such that their axis of rotation is essentiallyperpendicular to the radial direction of the main rotor body centreaxle. In case the axis of rotation of the cavitator fulfils both theabove described criteria, the axis of rotation will be essentiallyparallel to the tangential direction of the circle along which thecavitator rotates around the main rotor body centre axle. However, acavitator could also be designed such that its axis of rotation isparallel with the main rotor body axle. In general it is desired todesign the arrangement such that the centrifugal forces from therotation of a cavitator and the rotation around the main rotor bodycentre axle are designed to have positions where the centrifugal forcescooperate and work in the same direction while there are other positionsin the cavitator where the centrifugal forces counteract each other inorder to induce large pressure differences within a liquid in thecavitator.

The cavitator could be arranged such that the cavitator inlet isarranged at or close to the leading end of the cavitator and saidcavitator outlet arranged at or close to the trailing edge of thecavitators when the cavitators rotates with the main rotor body. In thiscase will the flow of liquid through the cavitator contribute to thepropulsive force for rotating the main rotor body.

The gas generator described above discloses different features of how agas generator according to the invention may be designed. However, thereare many different ways to design a gas generator within the scope ofthe invention. The basic principle is to provide a main rotor body withcavitators rotating with the main rotor body.

The invention further relates to a cavitator which may be suitably usedin a gas generator as disclosed above. The cavitator is provided with acavitator inlet and a cavitator outlet for a liquid to be cavitated inthe cavitator. The cavitator further comprises one or several cavitatorchannels having a cavitator channel inlet and a cavitator channeloutlet. The cavitator channel or channels are designed with cavitationinducing means such as flow guiding or flow restricting means, bended orcurved channels, wave shaped channel walls, protrusions and widenings,surface irregularities such as cavitation generating indentations or acombination thereof. The cavitation inducing means will contribute toprovide a differentiated pressure within a liquid flowing through thecavitators. The cavitator further comprises an outer cavitator statorand an inner cavitator rotor arranged to rotate relative said outercavitator stator. The cavitator is further designed to induce a rotationof the inner cavitator rotor by a liquid flow through the cavitator. Therotation of the inner cavitator rotor will in turn induce adifferentiated pressure within the liquid in the cavitator promotingcavitation in the liquid flowing through the cavitator channels. Hence,the rotation of the rotor will together with the cavitation inducingmeans in the cavitator channels provide for a cavitation of a liquidflowing there through due to the inertia of the liquid and thecentrifugal forces induced by the rotation of the main rotor body. Asthe liquid flows through the cavitator, the cavitator inducing meanswill cause a liquid flowing through the cavitators to change directions,at the macroscale or microscale, which will contribute to adifferentiated pressure within the liquid in the cavitator.

The cavitator channel or channels may be designed to be wave-, sawtooth- or curvilinear shaped. According to a specific shape of thecavitator channel or channels, they are designed to be shaped as sinuscurves. A sinusoidal shape has turned out to be advantageous in that itcreates pressure difference in the cross-sectional and the longitudinaldirection of the channels so as to increase cavitation.

The cavitator channel or channels, which are running along the axis ofrotation of the cavitator rotor, may be subdivided in an inner cavitatorchannel located closer to the axis of rotation of the cavitator rotorthan a second outer cavitator channel. The first inner channel is formedbetween a first, innermost wall and a second, middle wall in thecavitator forming a first inner flow path for a fluid and the second,outer channel is formed between the second, middle wall and a third,outermost wall (314 c) in the cavitator (3) forming a second outer flowpath for the fluid. The cavitator may be designed such that the innerwall and intermediate wall forms part of the cavitator rotor while theouter wall forms part of the cavitator stator.

In case the cavitator is designed with an inner and outer channel asdisclosed above, there may be capillary vanes between the first innerchannel and the second, outer channel. The capillary vanes are smallchannels formed in the intermediate wall between the outer and innercavitator channels which provides for fluid communication between theinner and outer cavitator channels.

The capillary vanes may be designed to function as jets for causing arotational movement of the inner cavitator rotor. Hence, by designingthe capillary vanes to not have a radial direction relative the axis ofrotation, the flow of liquid through the capillary vanes may cause arotational movement around the axis of rotation.

The capillary vanes could also be designed to increase cavitation for aliquid passing through the vanes. This may for example be achieved bydesigning the capillary vane inlet and outlet such that the capillaryvane outlet is wider than the capillary vane inlet. Designing thecapillary vane inlet narrower than the capillary vane outlet willcontribute to create a change of the pressure within the fluid passingthrough the capillary vanes. A liquid passing through the capillary vaneand entering a narrow inlet and exiting a wider outlet will be subjectedto a pressure decrease while flowing through the capillary vane and thusinduce a cavitation of the liquid passing through the vane. Thecapillary vanes may be designed to have a step less change of the width,e.g. being funnel shaped, or designed to have an abrupt change of thewidth between the capillary vane inlet and the capillary vane outlet,e.g. by having a constant smaller capillary width in the inlet sectionand a constant, larger width of the outlet section.

In order to cause a liquid to flow through the capillary vanes could thefirst inner cavitator channel be provided with a dead end. The flow ofliquid entering the inner cavitator channel inlet must thus to passthrough the capillary vanes from the inner cavitator channel to theouter cavitator channel which is provided with an outlet opening. Atleast the inner cavitator channel will have an inlet opening and theremay also be an inlet opening in the outer channel.

A cavitator comprising an inner and an outer cavitator channel may bedesigned such that said first, innermost wall and said secondintermediate wall in the cavitator form part of said inner cavitatorrotor while said, third, outer wall in the cavitator (3) forms part ofsaid outer cavitator stator.

A cavitator designed with capillary vanes between the inner and outerchannel for inducing a cavitation of the liquid passing through thecapillary vanes should preferably be designed to avoid the cavitation ofthe liquid to erode the cavitator channels. Cavitation is a knownphenomenon which erodes and ruins a material if it occurs on or adjacentto a surface, e.g. on boat propellers. The cavitator channels shouldthus be adapted such that the second outer cavitator channel is designedto have a width adapted to provide a sufficient distant for the gasbubbles formed by cavitation of the fluid, when flowing from the firstinner cavitator channel via the capillary vanes to the second outercavitator channel, to collapse inside the fluid before the cavitationbubbles reaches the outer wall of the second outer cavitator channel.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 discloses an embodiment of a gas generator

FIG. 2 discloses embodiments of a main rotor body

FIG. 3 discloses an embodiment of a cavitator

FIG. 4 discloses schematically the function of an embodiment of acavitator

FIG. 5 discloses a gas generator comprising a waste collection tank

DETAILED DESCRIPTION OF INVENTION

In FIG. 1 is disclosed an example of a gas generator 1 according to theinvention. The gas generator 1 exemplified in FIG. 1 comprises an outercasing 101 forming part of a static support framework. In this case isthe outer casing 101 designed as a cylinder having an envelope surface101 a, an upper wall 101 b and a bottom wall 101 c defining a containerspace inside the outer casing 101. The static support structure furthercomprises a liquid supply conduit 102 for supply of a liquid to the gasgenerator 1. The liquid is guided from the liquid supply conduit 102 toa liquid supply reservoir 104 via the space inside the outer casing.

In FIG. 1 b has a portion of the envelope surface 101 a been removed inorder to reveal the interior of the outer casing 101. Inside the outercasing 101 is an outer container space 105 formed between the outercasing 101 and an inner casing 106. The inner casing 106 also have agenerally cylindrical shape. In the outer container space 105 areprovided transfer conduits 103. The transfer conduits 103 are preferablydesigned and made from a material having high heat conductivity in orderto provide for an efficient heat exchange between the liquid inside thetransfer conduits and the outer container space 105. It is furtherprovided at least one outer container space outlet 107 in the bottomwall 101 c of the outer casing 101 in the outer container space 105. Theouter space container outlet 107 will serve as an outlet for gasproduced in the gas generator 1 which will condense in the outercontainer space 105.

In FIG. 1 c has a portion of the envelope surface of the inner casing106 been removed in order to reveal the inside of the inner casing 106defining an inner container space 108. In the inner container space 108is provided a main rotor body 2 comprising a main rotor body casing 201.The main rotor body casing 201 is bell shaped. The main rotor body 2 isarranged to rotate along an axis along the longitudinal extension of thecylinder shaped inner and outer casings 106, 101. When referring to therotational axis of the main rotor body in this description, the axiswill be referred to as the Y-axis.

In FIG. 1 d has a portion of the main rotor body casing 201 been removedin order to reveal the interior of the main rotor body casing 201defining a main rotor space 202. It is inside the main rotor space 202where the cavitators 3 (see FIGS. 2 and 3 ) are located and where theliquid is transformed from liquid to gas. Liquid is guided from theliquid supply reservoir 104 beneath the outer casing 101 via a rotorbody channel 203 having a rotor body channel inlet 204 connected to theliquid supply reservoir 104. The liquid will further be guided via therotor body channel 203 to cavitators (not shown) comprised in a toroidalcasing 208. The liquid will cavitate and be gasified in the cavitators 3and finally leave the toroidal casing 208 via the main rotor body gasfeed openings 210 in the toroidal casing 208. The gas flowing throughthe main rotor body gas feed openings 210 in the toroidal casing willflow towards a main rotor body outlet 205. The main rotor body outlet205 has a circular cross sectional opening which is adapted to fit intoan outer container space gas inlet 109 which is formed in an upper wall106 b of the inner casing 106. The outer container space gas inlet 109is funnel shaped and designed to encircle the main rotor body outlet 205and preferably designed such that the outer container space gas inlet109 overlap the main rotor body outlet 205 in the axial direction. Thereshould be a gap between the outer container space gas inlet 109 and themain rotor body outlet 205. The gap will not only prevent any undesiredcontact and friction between the rotating main rotor body 2 and thestationary outer container space gas inlet 109 but also this design willcontribute to a venturi effect when gas at high speed flows through themain rotor body outlet 205. This flow will strive to withdraw air fromthe inner container space 108 such that an under pressure or vacuum iscreated in the inner container space 108. The under pressure created inthe inner container space 108 will thus contribute to a desired lowerfrictional loss when the main rotor body 2 is rotating at very highspeeds.

In FIG. 1 d is also disclosed a centrally located flow restrictor 206.The flow restrictor 206 will, together with the funnel shaped walls ofthe main rotor body casing 201, form a flow restriction for the gas flowin the passage from the main rotor body gas feed openings 210 in thetoroidal casing to the main rotor body outlet 205. This restrictingarrangement will cause particulate matter, even very small particlessuch as salt, to be subject to centrifugal forces arising from hittingthe flow restrictor 206 or the walls of the main rotor body casing 201which will make them deviate from forming part of the main flow of gasdirected to the main rotor body outlet 205 such that there willessentially only be gas leaving the main rotor space 202 while particlesand some of the gas will be falling down towards the bottom of the mainrotor space, essentially along the walls of the main rotor body casing202. In case the gas generator 1 is used for desalination of salt water,there will be vapour essentially free from any salt (and otherparticles) leaving the main rotor body outlet 205 while there will be aconcentrated brine flowing along the walls of the main rotor body casing201.

The general flow of a liquid to be gasified and thereafter condensedonce more while impurities are removed may be briefly described withreference to FIGS. 1 a to 1 d as follows. A liquid enters into the gasgenerator 1 from a liquid supply conduit 102 to a liquid supplyreservoir 104 via transfer conduits 103 located in the outer containerspace. The liquid will be guided from the liquid supply reservoir 104 tothe main rotor body 2 via a main rotor body channel 203 and guided tocavitators (not shown) which will gasify the liquid by cavitation. Theliquid flowing thorough the transfer conduits 103 will be preheated byheat exchange in the outer container space 105 with the gas produced bythe gasified liquid from the main rotor body 2. The gasified liquid isflowing out from the main rotor space 202 via main rotor body outlet and205 and outer container space gas inlet 107 to the outer container space105. As the gas will condense in the outer container space 105, it willfall down to the bottom wall of the outer casing 101 c wherefrom thecondensed gas is guided via the outer container space outlet 107 to adesired tank or reservoir. The impurities from the liquid, together withsome of the liquid which not follow the gas flow from the main rotorspace 202 will flow towards the bottom of the main rotor space 202 wherethere are one or several main rotor drainage outlets 207 for drainingthe liquid separated from the gas. The main rotor drainage outlets 207are guiding the liquid to a drainage collector 110 in the innercontainer space 108 which is provided with liquid waste conduits 111 forremoval of the waste liquid from the main rotor body 2.

In FIG. 2 a is shown a main rotor body 2 where the main rotor bodycasing 201 has been removed to disclose the design on the inside of themain rotor body 2. The main rotor body 2 comprises a circular toroidalcasing 208 which rotates around a centre axle 209 which will correspondto the Y-axis in the following schematically description of therotational arrangement below. There are three cavitators 3 arranged andevenly distributed in the toroidal casing 208 such that the main rotorbody 2 will be balanced. Hence, there should preferably be at least twocavitators comprised in the main rotor body 2 distributed equidistantfrom each other and on the same radial distant from the centre axle 209being the axis of rotation around which the main rotor body 2 rotates.Each cavitator 3 comprises a cavitator inlet 301 and a cavitator outlet302 which is located in connection with a main rotor body gas feedopening 210 in the toroidal casing. To be noted, the portion of thetoroidal casing 208 which is missing at the location of the cavitatorinlet 301 has only been removed in the drawing in order to make thecavitator inlet 301 visible in the drawing and this part is covered bythe toroidal casing 208 as shown for the other two cavitators.

In FIG. 2 b is disclosed a pump 211 in which the pump casing 212 hasbeen partly removed in order to reveal the pump main body 213 covered bythe pump casing 212. The pump main body 213 has been provided withhelically shaped cut-outs which together with the pump casing 212 formpump channels which thus form a screw pump, also commonly referred to asan Archimedean screw. The pump 211 is partly submerged into the liquidsupply reservoir 104 such that the pump channel inlets 215 are locatedbelow the surface level of the liquid in the liquid supply reservoir104. As the main rotor body 2 starts to rotate, in this case clockwise,liquid will be drawn upwards by the helically screw shaped channels andguided further to the cavitator inlets 301 by the rotational movement ofthe main rotor body. An additional pumping effect will also arise fromthe centrifugal forces acting on the liquid as it enters the pump 211.The liquid enters at or close to the centre axle 209 and is thereafterguided upwards and outwards through the pump channels. The pump channelsform part of the main rotor body channels 203. As is obvious from FIG. 2b , the liquid will follow the helical pattern of the pump channels asthe liquid rises up to the level of the toroidal casing 208 where afterthe channels will continue in an essentially radial direction towardsthe peripheral parts of the main rotor body 2 having an outlet in thetoroidal casing 208 close to the cavitator inlet 301.

Hence, the above FIGS. 1 a-d and 2 a-b disclose how a complete systemfor gasification by cavitation of a liquid may be designed. However,even though the system described have many beneficial features, theoverall system according to the invention may be designed in a moresimplistic way. In FIG. 2 c is disclosed how a more basic systemaccording to the invention may be designed. In FIG. 2 c is simplydisclosed a gas generator 1′ comprising a main rotor body 2′ providedwith a centre axle 209′ which is provided with a hollow inside formingpart of a channel 214′ for distribution of a liquid from a channel inlet204′ to a pair of cavitators 3′ located at diametrically opposite sidesof the rotational axis. The device could be provided with an Archimedeanscrew or having an additional pump unit but may also be designed withoutany additional pump equipment and rely on the centrifugal forces actingon the liquid as it flows through the channel 214′. Hence, the essentialfeatures for providing a gas generator 1 according to the invention aredisclosed in FIG. 2 c . In order to function as desired, the gasgenerator 1′ in FIG. 2 c as well as the gas generator 1 described inFIGS. 1 a-d and 2 a-b , shall be provided with a cavitator 3 which isdesigned as a small turbine in order to subject the liquid to furthercentrifugal forces from additional rotation in the cavitator. An exampleof the design of such a cavitator 3 will be described below withreference to FIGS. 3 and 4 .

With reference to FIGS. 3 a-3 f the design of the cavitator 3 will bedescribed. In FIG. 3 a is disclosed a cavitator 3 having a generallycylindrical outer shape. A cavitator inlet 301 is located at a firstaxial end of the cylindrical cavitator 3 and a cavitator outlet 302 atthe second, opposite axial end of the cylindrical cavitator 3. There arefurther disclosed an inlet cap 301 a with an inlet opening and an outletcap 302 a provided with outlet openings. The inlet and outlet caps 301a, 301 b may be used to direct and control the flow of fluid enteringand leaving the cavitator 3. However, the inlet and outlet caps 301 a,302 a could be designed different and the cavitator 3 will work alsowithout these caps 301 a, 301 b. In the following FIGS. 3 b to 3 e , thecaps have therefore been left out.

In FIG. 3 b is disclosed an exploded view of the cavitator 3 in FIG. 3 abut without caps. The cavitator 3 comprises an outer stator 303 whichforms a casing into which a cavitator rotor 304 is fitted. The cavitatorrotor 304 comprises an inner rotor piece 304 a and an outer rotor piece304 b which are designed to fit into each other and at least partlyoverlap each other in the axial direction.

In FIG. 3 c is shown a cross sectional view of the cavitator 3 (withoutcaps) wherein a cross sectional cut has been made dividing the cavitatorstator 303 in halves along its longitudinal extension. Also the outerrotor piece 304 b is shown in a cross sectional view where the crosssectional cut is dividing the outer cavitator rotor 304 b in halvesalong its longitudinal extension. However, the cross sectional cut ofthe outer cavitator rotor 304 b has been rotated somewhat relative thecut of the cavitator stator 303 such that the different parts are moreeasily recognized.

In the overlapping portion of the inner rotor piece 304 a and the outerrotor piece 304 b, the outer rotor piece 304 b is designed to enclosethe inner rotor piece 304 a such that there is gap in the radialdirection between the inner and outer rotor pieces 304 a, 304 b. The gapis extending the full circle between the inner and outer rotor pieces304 a, 304 b such that an annular shaped void space is created therebetween. The void space further extends in the longitudinal directionsuch that an inner cavitator channel 305 a is crated forming part of acavitator channel 305 (see FIGS. 3 e and 3 f ) for a fluid passingthrough the cavitator 3 from the cavitator inlet 301 to the cavitatoroutlet 302. In a similar manner, a void space is created in the radialdirection between the outer rotor piece 304 b and the cavitator stator303 creating an outer cavitator channel 305 b forming part of thecavitator channel 305.

The cavitator rotor in FIG. 3 c further comprises rotor blades 306located close to the cavitator inlet 301. The rotor blades 306 aredesigned to cause a rotation of the cavitator rotor 304 as the fluidflows through the cavitator 3. The fluid will pass the rotor blades andbe directed towards inner cavitator channel inlets 307 a and outercavitator channel inlets 307 b (see FIG. 3 e ). The inner cavitatorchannel is provided with a closed end 308 a while the outer cavitatorchannel is provided with an outlet 308 b close to the end of thecavitator 3 where the cavitator outlet 302 is located. A liquid enteringthe inner cavitator channel 305 a may thus not pass through an outlet atthe end of the inner cavitator channel. However, the inner cavitatorchannel 305 is separated from the outer cavitator channel by anintermediate wall 310 which is provided with capillary vanes 309connecting the inner cavitator channel 305 a with the outer cavitatorchannel 305 b. The fluid entering the inner cavitator channel 305 a willthus be directed via the capillary vanes to the outer cavitator channel305 b to be mixed with the flow in the outer cavitator channel 305 b toflow towards the outer cavitator channel outlet 308 a. The capillaryvanes 309 will serve as generators for cavitation of the fluid passingthrough them. The shape of the capillary vanes 309 disclosed herein hasa narrow inlet 311 in the side of the intermediate wall 310 facingtowards the inner cavitator channel 305 a and is widening towards itsoutlet 312 in the intermediate wall 310 at its side facing towards theouter cavitator channel 305 b. This shape will contribute to cavitationof the fluid passing through the capillary vanes as there will be areduced pressure as the capillary vane 309 widens towards the capillaryoutlet 312.

FIGS. 3 c and 3 d differs in that there are rotor blades 306 provided onthe cavitator rotor 304 in FIG. 3 c while there are no rotor bladespresent in FIG. 3 d . By designing the capillary vanes adequately theymay function as jet streams inducing a rotation of the cavitator rotor304. Hence, there are not necessarily present rotor blades on the rotor304 but it may also function with only the impulse from the fluidflowing through the capillary vanes in order to provide a rotation ofthe rotor.

In addition to the cavitation generated by the passage of the fluidthrough the capillary vanes 309, also the sinusoidal shape of thecavitator channels 305 a, 305 b together with the centrifugal forcesfrom the rotation of the cavitator rotor 304 will contribute to anincreased cavitation. In addition, there are also provided cavitationgenerating indentations 313 on the inner wall 314 of the cavitator innerchannel 305 a also improving the generation of cavitation.

It shall be noted that the explicit design of the cavitator 3 in FIGS. 3a-f only serves as an example of how cavitator suitably may be designedaccording to the invention. However, the cavitator could be designed inanother way. The important feature of the cavitator is that it isdesigned to include a cavitator stator 303 and a cavitator rotor suchthat there will be rotation of the cavitator channel 305 causing thefluid in the channel 305 to be subjected to centrifugal forces from therotation of the rotor 304. The theoretical theory beyond the design ofthe cavitator will be further explained in FIGS. 4 a -d.

In FIG. 4 a is disclosed how the forces acting on a liquid in a gasgenerator 1, 1′ as disclosed above are created and how they are used inthe gas generator. FIG. 4 a describes schematically how the cavitator 3rotates when it is mounted in the main rotor body 2 (see FIG. 2 ). Thecomplete cavitator 3 rotates around the Y1-axis, which is parallel tothe centre axle 209 in FIGS. 2 a and 2 c , and is thus subjected to afirst centrifugal force from this first rotation. The cavitator 3, e.g.such a cavitator as disclosed in FIGS. 3 a-3 f , is further designed andcomprised in the system such that the cavitator rotor 304 (see FIG. 3 )rotates relative the cavitator stator 303 (see FIG. 3 ) around a centreaxis through the cavitator 3. The centre axis of the cavitator isparallel with the Y0 . . . Y2 axis in FIG. 4 a . This second rotationwill cause centrifugal forces acting outwards in a direction from thecentre axis of the cavitator towards the envelope surface of thecylindrical cavitator all around the cavitator. Due to the constructionof the cavitator and how it is integrated in the main rotor body asdisclosed in FIGS. 2 a and 2 c , the centrifugal forces from the firstand second rotations will cooperate at different locations in differentways. The centrifugal forces from the first rotation around the Y1-axiswill be directed outwards from the Y1-axis in a direction perpendicularto the Y1-axis. The centrifugal forces from the second rotation of thecavitator rotor 304 relative the cavitator stator 303 will be directedoutwards from the Y0 . . . Y2-axis in a direction perpendicular to theY0 . . . Y2-axis. On the outside of the cavitator 3, i.e. the partfurthest away from the Y1-axis, the centrifugal forces from the firstrotation around the Y1-axis will act in an outward direction from theY1-axis. At this location, also the centrifugal forces from the secondrotation of the cavitator rotor 304 will be directed outward from theY1-axis. On the inside of the cavitator 3, i.e. the part closest to theY1-axis, the centrifugal forces from the first rotation around theY1-axis will still act in an outward direction from the Y1-axis whilethe centrifugal forces from the second rotation of the cavitator rotor304 will act in the opposite direction, i.e. towards the Y1-axis. Hence,the resulting centrifugal force from both rotations will change frombeing totally aligned on the outside to be working in oppositedirections on the inside. The resulting force will gradually change andwill also work in directions being along the Y1 axis along thecircumference of the cavitator. For example, in the mid portion betweenthe outside and inside, the force from the second rotation by thecavitator rotor will be directed along the Y1-axis but in differentdirections depending on if they are working on the upside or downside.

In FIG. 4 b is disclosed a cross sectional view of the cavitator 3 in aplane perpendicular to the centre axis through the cavitator 3, i.e.through the axis being parallel to the Y0 Y2-axis in FIG. 4 a . As canbe seen in FIG. 4 b , the capillary vanes 309 are designed to be slantedin the cavitator rotor intermediate wall 310. The slanted capillaryvanes 309 will contribute in providing a rotation of the cavitator rotor304 (see FIG. 2 ) when a liquid is forced to flow through the capillaryvanes 309 from the inner cavitator channel 305 a to the outer cavitatorchannel 305 b. The liquid flowing through the capillary vanes 309 willenter via a rather narrow capillary vane inlet 311 in the innercavitator channel 305 a and will be exhausted from a rather widecapillary vane outlet 312 in the outer cavitator channel 305 b. Thedesign of the capillary vanes 309 having a narrow inlet 311 and a wideoutlet 312 will contribute to cavitation of a liquid passing through thecapillary vanes 309.

In FIGS. 4 c and 4 d is schematically disclosed how the mechanism ofcavitation function in the cavitator 3. In FIG. 4 c is disclosed how aliquid passing through the capillary vane 309 will cavitate due to thepressure difference created from having a narrow capillary vane inlet311 and a wide capillary vane outlet 312. As the liquid flows throughthe capillary vane, the pressure reduction occurring when the liquid thenarrow capillary vane inlet portion and entering the capillary vaneoutlet portion will cause some of the liquid to transform to gas phaseand thus creates bubbles in the liquid flow passing through thecapillary vanes 309. The creation of bubbles by cavitation isschematically disclosed in FIG. 4 c where the somewhat larger dots inthe capillary vane outlet 312 zone represents molecules of a fluid whichhave cavitated and expanded from being in liquid phase to be in gasphase. As these molecules continue to flow into the liquid flow in theouter cavitator channel 305 b, the gas phase bubbles will implode andform part of the liquid flow in the outer channel 305 b. In FIG. 4 d isschematically disclosed a pressure profile in the cavitator 3 where thedots are intended to represent fluid molecules. As can be seen in FIG. 4d , the curved regions of the wave shaped inner and outer channels 305a, 305 b closest to the centre rotation axis of the cavitator 3 have aless dense pattern of molecules indicating a lower pressure in theseregions. In particular, the capillary vane outlet 312 zone has a verysparse occurrence of molecules indicating a very low pressure. A fluidentering the cavitator channel inlet 301 as a liquid will thus flow viathe cavitator inner and outer channels 305 a, 305 b where the liquidwill start to cavitate in the wave shaped channels 305 a, 305 b and beguided further to the cavitator outlet 302 where the fluid will expandto form a gas phase when leaving the cavitator.

In FIG. 5 is disclosed how the gas generator 1 according to anembodiment have been provided with a waste collector tank 112 to whichthe liquid waste conduits 111 are connected in order to collect thewaste flow from the main rotor body space 202. The waste conduit 111 isprovided with a waste conduit valve arrangement 113 in order to controlthe flow to and from the waste collector tank. The valve arrangement 113is important in order to be able to switch the collector tank 112 frombeing in a first filling mode when the waste collector tank 112 isfilled up with waste liquid and a second discarding mode when the wasteliquid is discarded from the tank. In the first filling mode, the valvearrangement 113 is set to allow waste liquid from the main rotordrainage outlet 207 to flow into the waste collector tank 112 via awaste tank pipe 114 while the outlet pipe 115 is closed. When the modeis switched to the second discarding mode, the waste conduit valvearrangement 113 should first be set to close the inlet flow from therotor drainage outlet 207 where after the outlet pipe 115 is opened upand allow the waste liquid to be discarded from the waste tank 112 viathe waste tank pipe 114 to the outlet pipe 115.

During the first filling mode will the waste collector tank 112 beconnected to the main rotor drainage outlet 207 via the liquid wasteconduits 111 and will thus have the same pressure as in the innercontainer space 108. As previously explained, the pressure in the innercontainer space will be close to vacuum or at least considerably belowthe surrounding normal atmospheric pressure where the gas generator 1 islocated. Due to the low pressure in the tank when in filling mode, thecontrol of the valves to be opened and closed in the right order isessential to avoid a sudden pressure fluctuation in the waste collectortank 112. Hence, the valve arrangement 113 should be controlled to neverallow the waste liquid conduits 111 to be open at the same time as theoutlet pipe 115 is open in order to reduce possible pressurefluctuations in the inner container space 108. The low pressuregenerated and maintained in the inner container space 108 is generateddue to the high velocity flow of gas generated by the cavitators 3attached to the main rotor body 2. The high velocity gas will leave thecavitators 3 via the main rotor body gas feed openings 210 in thetoroidal casing and enter the main rotor body space 202. The gas willflow towards the main rotor body outlet 205 while passing by a flowrestrictor 206. The flow restrictor 206 will, together with the funnelshaped outlet, cause the flow of gas to hit wither the flow restrictor206 or the walls of the main rotor body casing 201 causing impuritiesand particles withdrawn by the gas to flow downwards along the walls ofthe main rotor body casing 201. The gas will continue to flow throughthe funnel shaped outer container space gas inlet 109 and flow throughthe outer container space 105 and thus passing the transfer conduits 103such that there will be a heat exchange between the hot gas and theliquid flowing in the transfer conduits 103. Preferably is the heatexchanging controlled such that the gas will condense and be collectedas liquid at the bottom wall 101 c of the outer casing 101 in order tobe guided to the container outlet 107. The container outlet 107 may beconnected to a piping system for further transport of the condensed gasin the piping system or having a tap for filling up storage tanks.

1. A gas generator for gasification of liquids, e.g. vapour from water,said gas generator comprising a main rotor body being rotatably mountedto a static support framework such that the main rotor body is arrangedto rotate around a rotor body centre axle, said main rotor bodycomprising one or several main rotor body channels, provided with arotor body channel inlet and a rotor body channel outlet, for guiding aflow of a liquid from said rotor body channel inlet being located at adistance R1 in the radial direction from the rotor body centre axletowards said rotor body channel outlet being located at a distance R2 inthe radial direction from the rotor body centre axle wherein R2>R1 suchthat a liquid in the rotor body channel is forced from the rotor bodychannel inlet towards the rotor body channel outlet by centrifugalforces as the main rotor body rotates around the rotor body centre axle,said main rotor body further comprising one or several cavitators eachone comprising one or several cavitator channels provided with acavitator channel inlet (301) being located closer to R2 than R1 and acavitator channel outlet, said cavitator channel inlet being connectedto the rotor body channel outlet for guiding said liquid flow to thecavitator for cavitation of the liquid, said one or several cavitatorchannels is designed with cavitation inducing means, e.g. flow guidingor restricting means, wave shaped channel walls (314 a-c), protrusionsand widenings, surface irregularities such as cavitation generatingindentations or a combination thereof, in order to induce adifferentiated pressure within the liquid in the cavitator from theinertia of the liquid and the centrifugal forces induced by the rotationof the main rotor body thereby causing cavitation in the liquid flowingthrough the cavitator channels and the cavitation inducing means.
 2. Thegas generator according to claim 1 wherein said main rotor bodycomprises at least two cavitators being located equidistant from eachother and equidistant from the main rotor body centre axle.
 3. The gasgenerator according to claim 1 wherein the main rotor body comprises amain rotor body casing defining a rotatable container having an interiormain rotor body space to which the vaporized liquid is guided from thecavitators.
 4. The gas generator according to claim 3 wherein the mainrotor body space defined by the main rotor body casing is bell shaped orshaped as the lower half of an hour glass or as a truncated cone.
 5. Thegas generator according to claim 3 wherein the main rotor body casing(201) forming part of the main rotor body is designed to have a mainrotor body outlet at its upper portion having a reduced cross sectionalarea perpendicular to the rotor body centre axle as compared to thelower cross sectional area or the mean cross sectional area of therotatable container formed by the main rotor body casing (201).
 6. Thegas generator according to claim 3 wherein said main rotor body iscomprised in an inner casing forming part of the static supportstructure, said inner casing being used as a pressure chamber.
 7. Thegas generator according to claim 3 wherein the main rotor body outlet isdesigned to cooperate and fit into an outer container space gas inletcomprised in an inner casing upper wall (106 b) such that the openingshave an overlapping area, said outer container space gas inlet beingdesigned to have a larger cross sectional area than the main rotor bodyoutlet such that there is a gap created between an outer container spacegas inlet and the main rotor body outlet such that the flow of gas fromthe main rotor body space will create and maintain a low pressure zonein an inner container space due to the venturi effect of the flowinggas.
 8. The gas generator according to claim 3 wherein said main rotorbody space comprises a flow restrictor encircling the centre axle and islocated between the main rotor body gas feed openings and main rotorbody outlet, said flow restrictor causing solid matter contained in thegas to be separated from the gas flow when being hit by particlescomprised in the gas flow.
 9. The gas generator according to claim 3wherein said main rotor body space comprises main rotor drainage outletsin its lower plate for discarding solid matter separated from the gasflow together with a portion of the fluid.
 10. The gas generatoraccording to claim 1 wherein said device comprises a fixed outer casingin which a fixed inner casing defining a low pressure inner containerspace is comprised, said flow of gas from the inner container spacebeing guided via an outer container space gas inlet to the outercontainer space.
 11. The gas generator according to claim 10 whereinsaid outer container space further comprising liquid supply conduits inwhich liquid to be fed to the main rotor body is preheated by the gasgenerated in the main rotor body flowing through the outer containerspace.
 12. The gas generator according to claim 10 wherein the gasflowing through the outer container space is cooled down to condense inthe outer container space such that condensed gas may be collected fromthe outer container space via an outer container space outlet.
 13. Thegas generator according to claim 1 wherein the main rotor body isdesigned as a pump unit (211), e.g. a screw pump or Archimedean screw,in order to pump a liquid from a liquid supply reservoir via pumpchannels forming part of the main rotor body channels when the mainrotor body is rotating.
 14. The gas generator according to claim 1wherein the at least one cavitator is arranged to have an innercavitator rotor arranged to rotate relative an outer cavitator stator,said rotational movement being induced by designing the cavitator torotate by the water flowing through the cavitator from the cavitatorinlet (301) to the cavitator outlet.
 15. The gas generator according toclaim 14 wherein the cavitators are arranged with its axis of rotationbeing essentially perpendicular to the main rotor body centre axle beingthe axis of rotation of the main rotor body.
 16. The gas generatoraccording to claim 14 wherein the cavitators are arranged with its axisof rotation being essentially perpendicular to the radial direction ofthe main rotor body centre axle.
 17. The gas generator according toclaim 1 wherein said cavitator inlet is arranged at or close to theleading end of the cavitator and said cavitator outlet is arranged at orclose to the trailing edge of the cavitators when the cavitators rotateswith the main rotor body.